This invention is generally concerned with a system for monitoring a tire-condition value in a pneumatic tire and more particularly with a portable system for automatically monitoring a tire-condition value in a pneumatic tire of a moving vehicle.
It is known in the art to combine a passive radio frequency (RF) transponder, having a RF antenna, with a tire-condition sensor and to incorporate the resulting electronic tag with a pneumatic tire. The transponder typically includes an integrated circuit that is preferably a suitable complimentary, metal-oxide, semiconductor (CMOS). The integrated circuit generally includes a logic circuit and a read only memory (ROM) circuit connected thereto. The ROM circuit preferably has stored therein a unique serial number (SN) for identifying the electronic tire tag and thus the tire with which it is incorporated. In addition, the integrated circuit typically includes an analog to digital (A/D) converter circuit that is connected between the logic circuit and the sensor, for receiving and converting respective analog sample signals received from the sensor to respective related digital signals for processing by the logic circuit. Moreover, the integrated circuit typically includes an RF rectifier circuit that is connected between the RF antenna and the logic circuit, for receiving therefrom and rectifying an RF signal, transmitted from an external transceiver, for providing a direct current (DC) power input signal to the logic circuit. Still further, the integrated circuit includes a clock signal generating circuit that is also connected between the RF antenna and the logic circuit for receiving the RF signal and generating there from a suitable timing signal for use by the logic circuit. Moreover, the logic circuit includes a transmitter circuit. And, the logic circuit is constructed and arranged to respond to receiving the DC power input signal for energizing the ROM circuit, the A/D converter circuit and the sensor, and for causing the transmitter circuit to transmit to an external transceiver, data corresponding to the SN and to the then current sample signal received from the sensor.
The above-described electronic tire tag is typically incorporated with a pneumatic tire by initially encapsulating the tag in a rigid or semi-rigid material, such as a urethane, epoxy or polystyrene resin, hard rubber compound or the like. Thereafter, the encapsulated tag is normally wrapped with a green rubber material to form a patch that is fixedly secured to a previously cured pneumatic tire. Alternatively, the encapsulated tag may be included between respective layers of green-rubber material forming an uncured tire and vulcanized therewith, to form a cured pneumatic tire having the encapsulated electronic tire tag embedded therein.
As shown in U.S. Pat. No. 5,712,609 (""609), issued Jan. 27, 1998 to Mehregany et al., it is also known in the art to provide a micro-mechanical temperature condition sensor, fabricated on a silicon or bimetallic substrate, that is constructed and arranged for sensing a threshold temperature value. As discussed in the ""609 Patent, during normal temperature conditions the micro-mechanical temperature condition sensor is in the unlatched state. When an extreme temperature condition eventuates and is sensed by a micro-mechanical temperature sensor, the sensor latches and remains latched to provide a memory of the event available for detection purposes. Due to such characteristics, the micro-mechanical temperature sensor has come to be known in the art as a maximum temperature memory switch (MTMS). Assuming the provision of an MTMS as the sensor in the electronic tire tag discussed above, the A/D converter may be eliminated since the MTMS is a digital device. Moreover, the logic circuit would then be constructed and arranged to respond to energization thereof for performing a continuity detection test of the MTMS to determine the latched or unlatched state of the MTMS and to cause the transmitter circuit to transmit, to the external transceiver, data corresponding to the SN, followed by data corresponding the latched or unlatched state of the MTMS.
As shown in U.S. Pat. No. 4,067,235, issued Jan. 10, 1978 to Markland et al., it is also known in the art to provide a system for remotely measuring the air pressure in a pneumatic tire. The system calls for the provision of an electronic tire tag that includes a passive transponder and a pressure sensor in a pneumatic tire. In addition, externally of the tire, the system includes a stationary power transmitter that generates an electromagnetic field in the roadway with a flat coil antenna for empowering the transponder and pressure sensor. Moreover, the system includes a signal processor. When the pressure sensor is empowered, the sensor transmits a low frequency FM signal representative of the tire pressure to the signal processor. Whereupon the signal processor generates quantitative signals representing the pressure in the tire, and visually displays and passes such signals to a computer. By means of various flat coil antenna configurations, the system can distinguish between tires mounted in various relationships. Moreover, by coding the FM signal, the system can uniquely identify the vehicle as well as each tire thereof. In an additional embodiment, a current induced therein by an external magnetic field powers the pressure sensor. This embodiment calls for the pressure sensor in the tire to be rotated through a stationary magnetic field generated by permanent magnets attached to the vehicle.
Moreover, as shown in International Patent Application Publication Number WO 90/12474, published Oct. 18, 1990, it is known in the art to provide a system for electronically identifying a vehicle tire having a coil and signal generator internally secured to the tire. As the vehicle and thus the tire moves in a predetermined path of travel, the signal generator in the tire responds to the presence of predetermined signals at the coil, that are received from an interrogator antenna oriented at an angle of substantially 45 degrees relative to the path of travel of the vehicle, by transmitting a unique signal identifying the signal generator.
Other publications of interest concerning the subject matter relating to the present invention are U.S. Pat. Nos. 3,752,960, 4,630,044 and 5,070,334.
According to the present invention, a system for monitoring a tire-condition value in a pneumatic tire is provided. An aspect of the invention is to provide a portable system for automatically monitoring a tire condition value in a pneumatic tire of a moving vehicle. Yet another aspect of the invention is to provide portable ramp apparatus for use with a system for monitoring a tire condition value in a pneumatic tire.
According to the invention there is provided a system of apparatus for monitoring at least one tire condition value in each of a plurality of pneumatic tires of a moving vehicle, wherein each of the tires has associated therewith a passive electronic tire tag for sensing the at least one tire condition value and is responsive to an interrogation signal transmitted thereto to transmit a data modulated signal representative of the at least one tire condition value. The monitoring system includes portable ramp apparatus for supporting the moving vehicle and portable vehicle sensing apparatus for sensing the presence of the moving vehicle and tire pressure sensing apparatus embedded in the ramp apparatus for detecting the presence thereon of a vehicle tire on the ramp apparatus. In addition, the monitoring system includes transmitter antenna structure and receiver antenna structure respectively embedded in the ramp apparatus. The transceiver apparatus is operable for causing the transmitter antenna structure to transmit the interrogation signal thereof to the respective tire tags when the tire pressure sensing apparatus detects the vehicle tire. In addition, the transceiver apparatus is operable for causing the receiver antenna structure to receive the respective data modulated tire tag signals independently of one another from different tire tags. And, the transceiver apparatus is operable for demodulating the respective data modulated tire tag signals and digitizing data therefrom.
The ramp apparatus may include left and right ramp structures, and each of the ramp structures may be made of a vulcanized rubber material. Alternatively, each ramp structures may be made of a plurality of sheets of plywood. In addition, the tire pressure sensing apparatus may include at least one left and at least one right, tire pressure sensing structure. Further, the transmitter antenna structure may include left and right transmitter antennas respectively embedded in the left and right ramp structures. Further, the receiver antenna structures may include at least one left, and at least one right, receiver antenna, respectively embedded in the left, and right, ramp structures. Still further, the transceiver apparatus may include left and right transmitter antenna driver circuits that are respectively removably electrically connected to the left and transmitter antenna structures. Moreover, the transceiver apparatus may include a plurality of micro-controller circuits, the transceiver apparatus include left and right transmitter antenna driver circuits, and the left and right transmitter antenna structures, respectively, include the left and right antenna driver circuit, respectively, and, the right transmitter antenna the left and right antenna structures may be removably electrically connected to different micro-controller circuits.
Furthermore, the monitoring system may include portable computer apparatus removably electrically connected to the transceiver apparatus for controlling the transceiver apparatus. In addition, the computer may be removably electrically connected to the vehicle sensing apparatus for receiving therefrom a vehicle sensing signal indicating the presence of the moving vehicle. Still further the computer apparatus may be programmed for providing an enabling signal to the transceiver apparatus when the computer apparatus receives the vehicle sensing signal for causing the transceiver apparatus to enable operation thereof. Further, the computer apparatus may be programmed for providing a disabling signal to the transceiver apparatus when the computer apparatus stops receiving the vehicle sensing signal for causing the transceiver apparatus to disable operation thereof. Moreover, the portable computer apparatus may be removably electrically connected to tire pressure sensing apparatus for receiving therefrom a tire pressure sensing signal indicating that a vehicle tire is on the ramp apparatus. And, the computer apparatus may be programmed for providing a start interrogation signal to the transceiver apparatus upon receiving the tire pressure sensing signal, causing operation of the transmitter antenna structure for causing the transmission thereby of an interrogation signal thereof to the respective tire tags. In addition, the computer apparatus may be programmed for commencing a count of a predetermined time interval when the computer apparatus stops receiving the tire pressure sensing signal. Further, the computer apparatus may be programmed for providing a stop interrogation signal to the transceiver apparatus for discontinuance thereby of the interrogation signal thereof when the count ends.
Preferably, when the receiver antenna structure receives the respective data modulated tire tag signals from the tire tags, the transceiver apparatus demodulates the respective data modulated tire tag signals. In addition, the transceiver apparatus may also include at least one micro-controller circuit programmed for digitizing the respective demodulated tire tag signals and providing respective digital data signals to the computer apparatus that include the data digitized from the demodulated tire tag signals. Moreover, the computer apparatus may be programmed for processing the digital data signals for obtaining therefrom data corresponding to the at least one tire condition value transmitted thereto by each of the tire tags.
Preferably, each of the at least one tire condition values is selected from a group consisting of a tire air pressure value, a tire air temperature value, an internal tire temperature value and an MTMS status bit. Preferably, each of the tire tags includes a different serial number 36 and the computer apparatus may be programmed for processing the digital data signals for obtaining therefrom data corresponding to the respective tire tag serial numbers 36
Moreover, the monitoring system may include ambient pressure and temperature measuring apparatus conventionally electrically connected to the computer apparatus 290, for respectively providing thereto pressure and temperature signals respectively representative of a current ambient pressure and a current ambient temperature. And, the computer apparatus may be programmed for calculating an adjusted pressure and temperature value, respectively, in consideration of the current ambient pressure and temperature values.
Further, the computer apparatus may include a display, and the computer apparatus may be programmed for sorting and displaying the data corresponding to the respective digital data signals received from the at least one micro-controller circuit. And, the computer apparatus may be programmed for storing for historical record keeping purposes the data corresponding to the respective digital data signals received from the at least one micro-controller circuit and data corresponding to the number and configuration relative to one another of the respective vehicle tires.
According to the invention there is also provided portable ramp apparatus and structures embedded therein for monitoring at least one tire condition value in each of a plurality of pneumatic tires of a moving vehicle, wherein the moving vehicle has a left side thereof and a right side thereof. The ramp apparatus and embedded structures include portable left and right ramp structures for respectively supporting the left side and right sides of the moving vehicle. In addition, the ramp apparatus and embedded structures include at least one left, and at least one right, tire sensing structure, respectively embedded in the left, and right, ramp structures. Further, the ramp apparatus and embedded structures include left and right transmitter antenna structures, respectively embedded in the left and right ramp structures. And, the ramp apparatus and embedded structures include at least one left, and at least one right, receiver antenna structure, respectively embedded in the left, and right, ramp structures.
Each of the ramp structures may be made of a vulcanized rubber material. Alternatively, each of the ramp structures may be made of a plurality of sheets of plywood. Further, the tire pressure sensing structure may include a single pole, double throw, pressure sensitive switch, and a resilient potting material associated therewith for respectively actuating and de-actuating the associated switch when the moving vehicle rolls thereon and thereof. Moreover, each of the transmitter antenna structures may include a transmitter antenna and a transmitter antenna driver circuit therefor. In addition, the ramp apparatus may include a front end portion, a rear end portion and a mid-portion extending therebetween, wherein the front end portion is inclined upwardly and rearwardly to the mid-portion, and wherein the rear end portion is inclined downwardly and rearwardly from the mid-portion. Still further, the at least one receiver antenna structure may include a plurality of left receiver antennas, the at least one right receiver antenna structure may include a plurality of right receiver antennas, the moving vehicle may have a path of travel, and each of the receiver antennas may be oriented at an angle of substantially 45 degrees relative to the path of travel. In addition each of the transmitter antenna structures may include a transmitter antenna tuned to a frequency of substantially 125 Khz. Further, each of the at least one left and right receiver antenna structures may include a receiver antenna tuned to a frequency of substantially 62.5 KHz.
Other aspects, features and advantages of the invention will become apparent in light of the following description thereof.